Method of producing sheet-metal elbows.



A. DIECKMANN.

METHOD OF PRODUCING SHEET METAL ELBOWS.

APPLICATION FILED 0CT.18, 1911.

1,157,852. Patented 001. 26, 1915.

2 SHEETSSHEET I.

@627 .2 35 'Q,W,MLQ

A. DIECKMANN.

METHOD OF PRODUCiNG SHEET METAL ELBOWS.

APPLICATION FILED OCT. 18. I911.

w'mm Patented Oct. 26, 1915.

2 SHEETSSHEET 2.

AnoLr nInoKr/IANN, or CINCINNATI, 01-110.

METHOD on PRODUCING sneer-METAL ELB'ows.

mavens.

Specification of Letters Patent.

Patented on. as, rare.

Application fi1e'd outwei- 1a, 1911. Serial No. 655,278.

To all whom it may concern:

Be it known that I, ADoLr DIECKMANN, a citizen of the United States, residing at Cincinnati, in the county of Hamilton and State of Ohio, have invented certain new and useful Improvements in Methods of Producing Sheet-Metal Elbows, of which the following is a specification.

My invention relates to improvements in the art of producing sheet metal elbows of corrugated, polygonal, and similar cross sectional pattern.

One of its objects is to produce such sheet metal elbows with a minimum strain upon the sheet metal of the elbow- Another object 'is to produce such elbows, particularly of heavier gage material, with a minimum strain upon the mechanism employed.

Another object is to provide for the use of a mandrel of materially less diameter than the elbow to facilitate feeding the elbow over the mandrel.

Another object is to produce such elbows of interchangeable accuracy, and free from cracks or fractures.

My invention further consists in certain details, and order of procedure, all of which will be fully set forth in the description of the accompanying drawings in which;

Figure 1 is a perspective view of a sheet metal elbow previous to being corrugated. Fig. 2 is a detail sectional view through a portion of the elbow Fig. 1 illustrating the manner of forming the circumferential folds, or crimps. Fig. 3 is a perspective view of a corrugated elbow. Fig. 1 is a perspective view of another type of corrugated elbow. Fig. 5 is a plan view of the movable die actuating member of Figs. 7

and 8 detached. Fig. 6 is a sectional detail on line a e of Fig. 8. Fig. 7 is a central vertical section through the elbow corrugating mechanism showing the mandrel and part of the dies in side elevation. Fig. 8 is a front elevation of the mechanism illustrated in Fig. 7. Fig. 9 is a plan View of one of the movable dies detached. Fig. 10 is a sectional detail of the dies and mandrel, and an elbow being acted upon thereby.

The accompanying drawings represent the preferred embodiment of my invention.

A plain cylindrical sheet metal elbow A such as illustrated in Fig. 1 is first formed, preferably from a single sheet of metal and with the surplus metal taken up on one side to form the curve by lapped circumferential folds or crimps 2 by means known to the art.

A considerable percentage of elbows for commercial use are desired to be corrugated longitudinally in order to resist the action of water freezing thereinand to interchangeably telescope with corrugated straight pipe sections, while others are desired for ornamental or similar purposes to be shaped in cross section to various polygonal and similar cross sectional patterns. By my improved method I am enabled to produce elbows having various corrugated, polygonal and similar cross sectional patterns, all from a common type of plain cylindrical elbow such as illustrated in Fig. 1 without excessively straining or fracturing the metal, and of such accuracy and uniformity as to enable elbows of like pattern to be used in terchangeably one for another.

In carrying out my improved process, I provide a curved mandrel B rigidly attached by its shank Z) to a frame D with the free end of the mandrel projecting through an opening 3 1n said frame. A plurality of radlally movable dies 4- are mounted in guides 5 on the frame D so as to be able to move to and from the mandrelB. The dies 41 are slotted at 6 for the passage of stud bolts 7 which are rigidly attached to the frame D. Each die is also provided with a stud bolt 8. A link 9 is pivoted to each. bolt 7 and a link 10 is pivoted to each bolt and said links 9 and 10 are pivotally connected together in pairs by bolts 11 which also pass through. slots 7 in a circular die actuating member 12. Said die actuating member is mounted upon the frame D by means of stud bolts 72. passing through elongated apertures 13in the member 12, which slots limit the movement of member 12 to a reciprocating movement concentrically about the mandrel B. One or more eccentric shafts 141 provided with eccentrics 15, eccentric straps 16 and connecting rods 17 connecting said eccentrics to said member 12, serve to actuate said member 12. y

The movements of member 12 serve to shift the centers of bolts 11 into line with the centers 7 and 8 to move the dies toward the mandrel, and out of line with the centers 7 and 8 to move the dies away from the mandrel. The elongated apertures f are so placed upon the member 12 as to cause alternate dies to move in.. opposite directions at each change in the direction of movement of the member 12, thus in Fig. 8 three ofthe dies are shown acting upon the mandrel and three dies retracted from the mandrel, and in Fig. 10 two dies are acting upon the mandrel and two dies are retracted. As'many diesas desired may be employed, usually an even number of dies; This arrangement for the movement of alternate dies in opposite directions permits meto employ a mandrel of considerablyless diameter than the internal diameter of the elbow to be treated, and permits the springing away from the mandrel of a section of the metal of the elbow on each side of the dies acting upon the elbow as more clearly indicated in Fig. 10, where the two dies 20 at the sides are acting upon and forcing the metal 21 of the elbow against the mandrel B, while the upper and lower dies 20 are retracted and the metal of the elbow opposite said upper and lower dies stands away from the mandrel. Thesame effect is attained with the mandrel and dies illustrated in Figs. 7 and 8. In practice the cylindrical elbow is fed forward onto the free end of the mandrel and between the dies, and the corrugated or polygonal pattern is progressively impressed thereon the full length of the elbow, which is then withdrawn, during which movement it is further subjected to the action of the dies,

and if necessary, due to heavy gage elbow material, may be reinserted between the dies. The use of a mandrel of smaller diameter than the elbow facilitates the initial feeding of the cylindrical elbow over the mandrel, and the action of alternate dies upon the elbow at different intervals prevents strain- I ing or stretching the metal of the elbow over the projecting faces of the mandrel so as to distort, injure, or fracture the metal of the elbow, and enables elbows of accuracy and strength to be produced. Mandrels and dies of different cross sectional patterns are designed to be substituted for those illustrated whenever it is desired to change the pattern of the elbows produced. j

My invention as herein illustrated and de- Gopies of this patent may be obtained for scribed is capable of considerable modification without departing from the principle thereof.

Having described my invention, what I claim is:

1. The method of producing sheet metal elbows of corrugated or similar cross sectional pattern, which comprises bending the periphery of a section of a plain elbow at symmetrically disposed points by opposed internal and external pressures, releasing said bending pressures, bending the periphery at different symmetrically disposed points by like pressures, and continuing the above recited operations in sequence the desired distance around and along the elbow.

2. The method of producing sheet metal elbows of cross sectional pattern other than circular, which comprises bending the periphery of a longitudinal section of an elbow of circular cross section at symmetrically disposed points by the internal pressure of a mandrel of substantially less diameter than the elbow and opposed external pressures, releasing said bending pressures, bending the periphery at different symmet' rically disposed points by like pressures, and continuing the above recited operations in sequence the desired distance around and along the elbow.

3. The method of producing sheet metal elbows of corrugated or similar cross sectional pattern, which comprises bending the periphery of a section of a plain elbow at diametrically opposite points by opposed internal and external pressures, releasing said bending pressures, bending the periphery at difi'erent diametrically opposite points by like pressures, and continuing the above operations in sequence the desired distance around and along the elbow.

In testimony whereof I have aflixed my signature in presence of two witnesses.

ADOLF DIECKMANN.

Witnesses:

G. W. MILES, W. THORNTON BOGERT.

five cents each, by addressing the Commissioner of Patents, Washington, D. 0. 

